I. Field of the Invention
The present invention relates to a monoclonal antibodies useful for diagnosing cancers, inflammation and Alzheimer's disease and hybridomas producing the same. The present invention also relates to human .alpha..sub.1 -antichymotrypsin and methods for detecting or quantifying the human .alpha..sub.1 -antichymotrypsin.
II. Description of the Related Art
Human .alpha..sub.1 -antichymotrypsin (hereinafter also referred to as "ACT") is a glycoprotein which inhibits the protease activity of chymotrypsin, and is contained in body fluids such as blood. It is thought that the role of ACT is to protect the body by inhibiting the protease activities of bacteria and the like. It is known that the ACT levels in the body fluids of patients suffering from inflammation, cancers such as liver cancer, or Alzheimer's disease are higher than those of normal humans. Thus, it is now tried to diagnose these diseases by measuring the ACT levels in the body fluids.
The measurement of ACT is conventionally carried out by immunoassays or by measuring the inhibitor activity of ACT based on the inhibition of the chymotrypsin activity. However, the method in which the inhibitor activity is measured has drawbacks in that the operation is troublesome and the results are not accurate. As the immunoassays for measuring ACT, the SRID method and sandwich method which employ a polyclonal antibody have been carried out. However, as described later in detail, the present inventors discovered that ACT is a mixture of a plurality of ACTs. Thus, by the method in which the polyclonal antibody is employed, the total ACTs are measured since the polyclonal antibody reacts with the total ACTs. Therefore, although the measurement of the total ACTs has some diagnostic significance, the significance is less than that attained by measuring a specific ACT in the total ACTs.